Potential use of isovolumic contraction velocity in assessment of left ventricular contractility in man: A simultaneous pulsed Doppler tissue imaging and cardiac catheterization study.

AIMS: Echocardiographic techniques have so far provided suboptimal estimates of myocardial contractility in humans. Longitudinal myocardial motion during the isovolumic contraction (IVC) phase, measured by colour tissue Doppler imaging (TDI), has recently been shown in experimental animal models to reflect the state of myocardial contractility. The aim of the present study was to investigate the relationship between left ventricular (LV) isovolumic contraction velocities (IVCv) using pulsed Doppler tissue imaging (DTI) and global LV contractility as measured during cardiac catheterization. METHODS AND RESULTS: Cardiac catheterization and pulsed DTI were simultaneously performed in 16 consecutive patients (13 males, mean age 55+/-10years) with a variety of cardiac diseases. Relationships between the peak positive IVCv as measured at basal levels of the lateral, septal, anterior and posterior walls and the first derivative of LV pressure (+dP/dt(max)), were investigated. Peak IVCv measurements were obtainable in 81-100% of the four LV wall segments. Statistically significant linear relationships were found between IVCv and +dP/dt(max) at the lateral (r=0.58, P<0.05), septal (r=0.66, P<0.01), anterior (r=0.73, P<0.01) and posterior (r=0.81, P<0.001) segments of the LV. CONCLUSION: IVCv of the basal four LV walls correlates strongly with peak +dP/dt. IVCv is a readily obtainable non-invasive parameter, which correlates with the classical invasive measurement of global LV contractility. It appears likely that there are regional differences in wall motion when DTI is used to determine state of LV contractility.     

Noninvasive assessment of left atrial maximum dP/dt by a combination of transmitral and pulmonary venous flow.

OBJECTIVES: The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography. BACKGROUND: Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in LA volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (LA dP/dt(max)). METHODS: Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous LA pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with a micromanometer catheter, and LA dP/dt(max) during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive a multilinear regression equation to estimate LA dP/dt(max) from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. A previously validated numeric model was used to confirm these results. RESULTS: In the study group, LA dP/dt(max) showed a linear relation with LA pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with LA dP/dt(max) (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate LA dP/dt(max) with an r2 > 0.30. By stepwise and multiple linear regression analysis, LA dP/dt(max) was best described as follows: LA dP/dt(max) = 0.1 M-AC +/- 1.8 P-V - 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity of pulmonary venous flow during atrial contraction. This equation was tested in the latter 10 patients of the test group. Predicted and measured LA dP/dt(max) correlated well (r = 0.90, p < 0.0001). Numerical simulation verified that this relationship held across a wide range of atrial elastance, ventricular relaxation and systolic function, with LA dP/dt(max) predicted by the above equation with r = 0.94. CONCLUSIONS: A combination of transmitral and pulmonary venous flow parameters can provide a hemodynamic assessment of LA systolic function.     

Quantitative analysis of systolic function of the right ventricule by Doppler echocardiography

The recording of the velocity of tricuspid valve regurgitation by continuous wave Doppler enables the calculation of the instantaneous systolic pressure gradient between the right ventricle and right atrium. As right atrial pressure is relatively constant, the rate of acceleration of the regurgitant jet reflects the quality of the rise in pressure in the right ventricle in early diastole, and therefore right ventricular contractility. The authors studied 3 Doppler parameters of the rate of velocity increase of the tricuspid regurgitation; the maximum rate of acceleration (dV/dt max), the maximum derivative of the pressure (dP/dt max) and the mean rate of increase in pressure (T). The interobserver variability of these indices is low (r greater than 0.96); reproducibility is good in patients with sinus rhythm but mediocre in atrial fibrillation. The comparison of the Doppler indices with the right ventricular isotopic fraction in 26 patients with tricuspid regurgitation showed a good correlation (dV/dt max, r = 0.79, p less than 0.0001; dP/dt max, r = 0.69, p less than 0.0001; T, r = 0.60, p = 0.0012). These results show that right ventricular systolic function can be evaluated by continuous wave cardiac Doppler by recording the spectral envelope of tricuspid regurgitation.     

Noninvasive estimation of the instantaneous first derivative of left ventricular pressure using continuous-wave Doppler echocardiography

BACKGROUND. The complete continuous-wave Doppler mitral regurgitant velocity curve should allow reconstruction of the ventriculoatrial (VA) pressure gradient from mitral valve closure to opening, including left ventricular (LV) isovolumic contraction, ejection, and isovolumic relaxation. Assuming that the left atrial pressure fluctuation is relatively minor in comparison with the corresponding LV pressure changes during systole, the first derivative of the Doppler-derived VA pressure gradient curve (Doppler dP/dt) might be used to estimate the LV dP/dt curve, previously measurable only at catheterization (catheter dP/dt). METHODS AND RESULTS. This hypothesis was examined in an in vivo mitral regurgitant model during 30 hemodynamic stages in eight dogs. Contractility and relaxation were altered by inotropic stimulation and hypothermia. The Doppler mitral regurgitant velocity spectrum was recorded along with simultaneously acquired micromanometer LV and left atrial pressures. The regurgitant velocity profiles were digitized and converted to VA pressure gradient curves using the simplified Bernoulli equation. The instantaneous dP/dt of the VA pressure gradient curve was then derived. The instantaneous Doppler-derived VA pressure gradients, instantaneous Doppler dP/dt, dP/dtmax, and -dP/dtmax were compared with corresponding catheter measurements. This method of estimating dP/dtmax from the instantaneous dP/dt curve was also compared with a previously proposed Doppler method of estimating dP/dtmax using the Doppler-derived mean rate of LV pressure rise over the time period between velocities of 1 and 3 m/sec on the ascending slope of the Doppler velocity spectrum. Both instantaneous Doppler-derived VA pressure gradients (r = 0.95, p less than 0.0001) and Doppler dP/dt (r = 0.92, p less than 0.0001) correlated well with corresponding measurements by catheter during systolic contraction and isovolumic relaxation (pooled data). The Doppler dP/dtmax (1,266 +/- 701 mm Hg/sec) also correlated well (r = 0.94) with the catheter dP/dtmax (1,200 +/- 573 mm Hg/sec). There was no difference between the two methods for measurement of dP/dtmax (p = NS). Although Doppler -dP/dtmax was slightly lower than the catheter measurement (961 +/- 511 versus 1,057 +/- 540 mm Hg/sec, p less than 0.01), the correlation between measurements by Doppler and catheter was excellent (r = 0.93, p less than 0.0001). The alternative method of mean isovolumic pressure rise (896 +/- 465 mm Hg/sec) underestimated the catheter dP/dtmax (1,200 +/- 573 mm Hg/sec) significantly (on average, 25%; p less than 0.001). CONCLUSIONS. The present study demonstrated an accurate and reliable noninvasive Doppler method for estimating instantaneous LV dP/dt, dP/dtmax, and -dP/dtmax.     

Comparison of Doppler derived haemodynamic variables and simultaneous high fidelity pressure measurements in severe pulmonary hypertension.

OBJECTIVE--To assess relations between right ventricular pressure measured with a high fidelity transducer tipped catheter and the characteristics of tricuspid regurgitation recorded with Doppler echocardiography. DESIGN--A prospective non-randomised study of patients with severe pulmonary hypertension referred for consideration of lung transplantation. SETTING--A tertiary referral centre for cardiac and pulmonary disease, with facilities for invasive and non-invasive investigation, and assessment for heart and heart-lung transplantation. PATIENTS--10 patients with severe pulmonary hypertension being considered for lung transplantation. ENDPOINTS--Peak right ventricular, pulmonary artery, and right atrial pressures; peak positive and negative right ventricular dP/dt; peak Doppler right ventricular-right atrial pressure drop; Doppler derived peak positive and negative right ventricular dP/dt; and time intervals of Q to peak right ventricular pressure and to peak positive and negative right ventricular dP/dt. RESULTS--The mean (SD) pulmonary artery systolic pressure was 109 (29) mm Hg. The peak Doppler right ventricular-right atrial pressure drop underestimated peak right ventricular pressure by 38 (21) mm Hg, and by 21 (18) mm Hg when the Doppler value was added to the measured right atrial pressure (P values < 0.05). This discrepancy was greater for higher pulmonary artery pressures. The timing of peak right ventricular pressure differed, with the Doppler value consistently shorter (mean difference 16 ms, P < 0.05). Values of peak positive and negative right ventricular dP/dt and the time intervals Q-peak positive right ventricular dP/dt and pulmonary closure to the end of the pressure pulse differed between the two techniques in individual patients, but not in a consistent or predictable way. CONCLUSIONS--Doppler echocardiography significantly underestimates the peak right ventricular pressure and the time interval to peak right ventricular pressure in pulmonary hypertension, particularly when severe. These differences may be related to orifice geometry. Digitisation of Doppler records of tricuspid regurgitation provides useful semiquantitative estimates of absolute values and timing of peak positive and negative right ventricular dP/dt. Clinically significant differences may exist, however, and must be considered in individual patients.     

Noninvasive estimation of max (dP/dt) of the left ventricle based on maximum aortic flow acceleration as measured by pulsed Doppler echocardiography

To obtain an index of left ventricular contractility, cardiac catheterization is necessary. In the present study, we ascertained whether max(dP/dt) could be obtained noninvasively in vivo based on the theoretical equation, max(dP/dt) not equal to rho cmax(du/dt), where rho is the density of blood, c is the pulse wave velocity of the aorta and max(du/dt) is the maximum acceleration of the aortic blood flow. This equation is based on the theory of pulse wave propagation, and was established in animal experiments. We further attempted to clarify the clinical usefulness of rho cmax(du/dt) by examining the effects of afterload and preload on rho cmax(du/dt). Twenty-seven patients without stenosis of their aortic valves and left ventricular outflow tracts were observed. During cardiac catheterization, we measured max(dP/dt) using a catheter-tip micromanometer, max (du/dt) using pulsed Doppler echocardiography and pulse wave velocity by simultaneously recording the femoral pulse wave and the carotid pulse wave. The measurements were performed at rest, before and after an increase in contractility with dobutamine administration, an increase in afterload with methoxamine administration and an increase in preload by leg elevation. There was good linear correlation (Y = 0.95X + 7.51, r = 0.84, p less than 0.0005) between max(dP/dt)[X] and rho cmax(du/dt)[Y] at rest. When the contractility was changed, rho cmax(du/dt) reflected changing of max(dP/dt). Moreover, when the afterload and preload were increased, the changing pattern of rho cmax(du/dt) was similar to that of max(dP/dt). Max(du/dt), index of cardiac performance previously proposed, showed a different changing pattern than max(dP/dt), indicating that max(du/dt) was influenced substantially by loading conditions. These results indicated that we can obtain max(dP/dt) noninvasively and reliably by measuring rho cmax(du/dt).     

Measurement of right ventricular dP/dt. A simultaneous/comparative hemodynamic and Doppler echocardiographic study]

Right ventricular systolic function is difficult to assess by Doppler echocardiography. We studied 14 patients with tricuspid regurgitation on Doppler echocardiographic examination with the object of determining an index of right ventricular contractility based on the continuous Doppler signal of the regurgitant jet. The rate of increase in right ventricular pressure was calculated between 2 points, V1 and V2, situated on the ascending limb of the velocity profile of the tricuspid regurgitation and compared with the dP/dt max measured simultaneously at right heart catheterisation. The different values of V1 and V2 were: 0 and 1 m/s, 0 and 2 m/s, 0.5 and 1.5 m/s, 1 and 2 m/s and 0.5 and 2 m/s. An excellent correlation was observed between the catheter dP/dt max and the rate of increase in pressure measured by Doppler between 0 and 2 m/s (r = 0.93; p = 0.0001) and between 0.5 and 2 m/s (r = 0.93; p = 0.0001). The correlation was not as close between 0 and 1 m/s (r = 0.69; p = 0.048) and there was no correlation with the measurements between 0.5 and 1.5 m/s and between 1 and 2 m/s. Doppler echocardiography could therefore be used for non-invasive assessment of right ventricular systolic function in clinical practice.     

Hemodynamics of the Mueller maneuver in man: right and left heart micromanometry and Doppler echocardiography

Ten subjects with normal hemodynamics were studied during elective cardiac catheterization with right and left heart multisensor micromanometry to assess hemodynamic responses to the Mueller maneuver. Simultaneous right and left circulatory hemodynamics and left ventricular, pulmonary arterial, and aortic pressures were recorded, in addition to pulmonary arterial and aortic flow velocities. Steady-state cardiac outputs were determined by thermal dilution. Aortic systolic and mean pressures were not significantly changed during the Mueller maneuver, in contrast to a lower diastolic (p = .019) and higher pulse pressure (p = .016). Mean right atrial pressure (+/- SE) decreased from 7 +/- 1 to -17 +/- 4 mm Hg (p = .0002) and the right atrial "x" descent was markedly accentuated. Left ventricular end-diastolic pressure decreased from 12 +/- 4 to -3 +/- 13 mm Hg (p = .0025). Systemic vascular resistance and left ventricular peak positive dP/dt were increased during the Mueller maneuver (p less than .02), cardiac output and stroke volume were reduced (p less than .05), and there was no significant change in heart rate. Right and left peak flow velocities showed a trend toward a bilateral decrease (right, p = .054; left, p greater than .1), and times to peak flow velocity were increased in the pulmonary artery (p = .007) and reduced in the aortic root (p = .03). Normal subjects were studied separately by pulsed Doppler echocardiography. During the sustained Mueller maneuver, the internal jugular and right ventricular dimensions decreased, and superior vena cava Doppler flow was reduced.(ABSTRACT TRUNCATED AT 250 WORDS)     

Doppler echocardiographic evaluation of pulmonary artery pressure in chronic obstructive pulmonary disease. A European multicentre study. Working Group on Noninvasive Evaluation of Pulmonary Artery Pressure. European Office of the World Health Organization, Copenhagen

The feasibility, reproducibility and reliability of Doppler echocardiography in evaluation of pulmonary artery pressure in patients with chronic obstructive pulmonary disease (COPD) were determined in a multicentre study. In 100 COPD patients with mean pulmonary artery pressure ranging from 10 to 62 mmHg at cardiac catheterization, pulmonary pressure estimation was attempted by four Doppler echocardiographic methods. These methods comprised the calculation of transtricuspid and transpulmonary pressure gradients from Doppler-detected tricuspid or pulmonary regurgitation, the evaluation of right ventricular outflow tract velocity profiles with the measurement of right ventricular systolic time intervals and the measurement of the right ventricular isovolumic relaxation time. In 98 (98%) patients at least one of the methods could be employed. A tricuspid regurgitation jet was detected in 47 (47%) patients but its quality was adequate for measurement in 30 (30%). Pulmonary regurgitation jet velocity was measured only in five cases. The standard error of estimate in testing intra- and interobserver reproducibility of Doppler systolic time intervals was less than 5%. The predictive value of right ventricular outflow tract acceleration time less than 90 ms in the identification of patients with mean pulmonary artery pressure greater than 20 mmHg was 80%. Of Doppler echocardiographic data, best correlations with mean pulmonary artery pressure were found for the transtricupid gradient (r = 0.73, SEE = 7.4 mmHg), for the right ventricular acceleration time (r = 0.65, SEE = 8 mmHg) and right ventricular isovolumic relaxation time (r = 0.61, SEE = 8.5 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Attempts at measuring pulmonary arterial pressure by means of Doppler echocardiography in patients with chronic lung disease

In 72 patients with severe chronic pulmonary or pulmonary vascular disease pulmonary arterial pressure was measured by means of right heart catheterization. Forty three patients had pulmonary hypertension, (32 +/- 11 mmHg) and 27 patients had normal pressure (14 +/- 3 mmHg). These patients were examined with continuous wave (CW) and pulsed wave (PW) Doppler echocardiography. The retrograde systolic tricuspid valve pressure gradient assessed with CW Doppler correlated with systolic pulmonary pressure (r = 0.92, p less than 0.001, SEE 7.7 mmHg) but was measurable in only 17 of the 70 patients. The flow velocity pattern in the right ventricular outflow tract could be recorded in 68 of the 70 patients. Acceleration time (AcT) from systolic flow onset to peak velocity correlated with mean pulmonary artery pressure (r = 0.72, p less than 0.001, SEE 8.3 mmHg). An AcT less than 90 msec had an 84% positive predictive value for pulmonary hypertension. Right ventricular isovolumic relaxation time could be measured in 59 of the 70 patients and correlated with systolic pulmonary artery pressure (r = 0.69, p less than 0.001, SEE 12.4 mmHg). No single Doppler method is at the same time easily applicable and accurate in prediction of pulmonary arterial pressure in patients with chronic lung diseases.     

Monophasic transmitral flow pattern with less increase in heart rate indicates left ventricular dysfunction.

When heart rate (HR) increases, mitral flow can become monophasic. Prolonged isovolumic contraction and relaxation time (ICT and IRT), directly related to left ventricular (LV) function, can potentially influence the HR with monophasic mitral flow. The present study investigated the relation between HR that causes monophasic flow and LV function. During diagnostic catheterization, HR was increased using right atrial pacing by 2 beats/min every 2 min in a stepwise manner until the development of monophasic mitral flow in 17 patients with normal sinus rhythm. ICT, IRT, end-diastolic and end-systolic LV volumes, LV ejection fraction, LV peak + and -dP/dt, peak (+dP/dt)/P, and the relaxation time constant (tau) were measured by Doppler echocardiography or catheterization when monophasic mitral flow developed. The monophasic HR varied from 74 to 106 beats/min. By univariate analysis, ICT (p<0.01, r2=0.73), LV peak +dP/dt (p<0.05, r2=0.37), peak (+dP/dt)/P (p<0.01, r2=0.71), peak -dP/dt (p<0.05, r2=0.25), and tau (p<0.05, r2=0.33) had a significant correlation with monophasic HR. By multivariate analysis, prolonged ICT and reduced LV peak -dP/dt independently contributed to monophasic mitral flow with less increase in HR. Monophasic mitral flow with less increase in HR indicates impaired LV systolic and diastolic function during isovolumic contraction and relaxation.     

Quantitative assessment of pulmonary hypertension in patients with tricuspid regurgitation using continuous wave Doppler ultrasound

Doppler ultrasound examination was performed in 69 patients with a variety of cardiopulmonary disorders who were undergoing bedside right heart catheterization. Patients were classified into two groups on the basis of hemodynamic findings. Group I consisted of 20 patients whose pulmonary artery systolic pressure was less than 35 mm Hg and Group II consisted of 49 patients whose pulmonary artery systolic pressure was 35 mm Hg or greater. Tricuspid regurgitation was detected by Doppler ultrasound in 2 of 20 Group I patients and 39 of 49 Group II patients (p less than 0.001). Twenty-six of 27 patients with pulmonary artery systolic pressure greater than 50 mm Hg had Doppler evidence of tricuspid regurgitation. In patients with tricuspid regurgitation, continuous wave Doppler ultrasound was used to measure the velocity of the regurgitant jet, and by applying the Bernoulli equation, the peak pressure gradient between the right ventricle and right atrium was calculated. There was a close correlation between the Doppler gradient and the pulmonary artery systolic pressure measured by cardiac catheterization (r = 0.97, standard error of the estimate = 4.9 mm Hg). Estimating the right atrial pressure clinically and adding it to the Doppler-determined right ventricular to right atrial pressure gradient was not necessary to achieve accurate results. These findings indicate that tricuspid regurgitation can be identified by Doppler ultrasound in a large proportion of patients with pulmonary hypertension, especially when the pulmonary artery pressure exceeds 50 mm Hg. Calculation of the right ventricular to right atrial pressure gradient in these patients provides an accurate noninvasive estimate of pulmonary artery systolic pressure.     

Continuous-wave Doppler in children with ventricular septal defect: noninvasive estimation of interventricular pressure gradient

Continuous-wave Doppler was used to estimate the pressure gradient between the right and left ventricles in 28 children with ventricular septal defect (VSD). Doppler measurement of maximal velocity was performed during cardiac catheterization and the Doppler-predicted gradient was compared with the peak-to-peak gradient measured simultaneously by catheter. Doppler gradients ranged from 10 to 71 mm Hg and correlated well with measured gradient (r = 0.97, p greater than or equal to 0.001). Fourteen patients had isolated VSD, and in these patients Doppler measurements of gradient allowed accurate estimation of right ventricular pressure (r = 0.93). There was an inverse correlation between the ratio of pulmonary to systemic resistance and maximal velocity (r = -0.77). Thus, continuous-wave Doppler is an accurate means of measuring instantaneous VSD pressure gradient in children with congenital heart disease and can be used to estimate the right ventricular and pulmonary artery pressure in children with isolated VSD. This noninvasive method can be used to distinguish restrictive from nonrestrictive VSD.     

Influence of acute changes in preload, afterload, contractile state and heart rate on ejection and isovolumic indices of myocardial contractility in man.

To determine the sensitivity of several isovolumic and ejection phase indices of myocardial contractility to loading, inotropic stimulation and heart rate in man, 14 patients (pts) were studied during cardiac catheterization with simultaneous recordings of left ventricular (LV) pressures and ultrasound dimensions. Measurements were made of instantaneous and mean circumferential fiber shortening velocity (VCF), maximal (max) rate of LV pressure rise (dP/dt), dPHdt divided by end-diastolic circumference [(dP/dt)/C], (DP/dt)/C divided by aortic valve opening pressure [(dP/dt/CP], PEAK CONTRACTILe element velocity (VCE) using total LV pressure, VCE extrapolated to zero total pressure (Vmax), VCE at a developed pressure of 10 mm Hg (VCEDP10) and dP/dt at a common isovolumic developed pressure of 40 mm Hg [(dP/dt)/DP40]. Resulta are expressed in per cent change of the mean for the group. Acute preload increase (8.6% increase in end-diastolic circumference) with volume expansion at constant heart rate in 7 pts produced insignificant changes in VSF, an 8.3% increase in max dP/dt, no change in (dP/dt)/C, a variable response in (dP/dt)/CP, 18% reduction in peak VCE, 16% reduction in Vmax, 14% increase in VCEDP10, and a 10% increase in (dP/dt)/DP40. An acute increase in afterload produced by angiotensin in 8 pts (44% increase in peak stress) led to a 38% decrease in VCF, a 2.5% increase in max dP/dt, no significant change in (dP/dt)/C, a 26% reduction in (dP/dt)/CP, variable responses in peak VCE and Vmax, an 11% increase in VCEDP10 and minor changes in (dP/dt)/DP40. All of the contractility indices were augmented significantly by isoproterenol and atrial pacing. In a given patient, max, dP/dt appears to be useful in the assessment of acute changes in inotropic state since the magnitude of its response to abrupt changes in preload is small and to afterload insignificant. Normalizing max dP/dt for end-diastolic circumference assures better stability during loading with good sensitivity to inotropic stimulation. VCF may be used whenever changes in afterload are minimal. The isovolumic measurements of VCE (regardless of whether total or developed pressure is used) lack sufficient stability during acute changes in loading conditions to warrant their use in the quantitative assessment of acute changes in inotropic state.     

Noninvasive assessment of left ventricular contractility in pediatric patients using the maximum rate of pressure rise in peripheral arteries

The maximum rate of left ventricular pressure rise (LV dp/dt(max)) is a good indicator of ventricular contractility. However, its measurement requires invasive cardiac catheterization. By applying the relationship between the ratio of aorta (Ao) dp/dt(max) to LV dp/dt(max) and the mean artery pressure (MAP), we tested the possible noninvasive estimation of LV dp/dt(max) by the maximum rate of pressure rise in peripheral arteries, as measured by tonometry. The study subjects were 31 children with cardiovascular disease. The LV and Ao pressures were measured during cardiac catheterization, with simultaneous recording of the brachial (BrA) or radial (RaA) artery pressure. The relationships between BrA dp/dt(max) and Ao dp/dt(max) and between RaA dp/dt(max) and Ao dp/dt(max) were determined (Ao dp/dt(max) = 0.299 × BrA dp/dt(max) + 210.6, n = 17, r = 0.78, SEE = 74.0, P = 0.0002, and Ao dp/dt(max) = 1.442 × RaA dp/dt(max) + 165.9, n = 14, r = 0.87, SEE = 66.1, P = 0.0001). Using these relationships and the equation Ao dp/dt(max)/LV dp/dt(max) = 0.694 - 4.00 × 10(-3) × MAP, LV dp/dt(max) was estimated from BrA dp/dt(max) or RaA dp/dt(max). The estimated LV dp/dt(max) correlated well with the measured LV dp/dt(max) independent of the site of measurement (y = 0.912 × x + 112.9, r = 0.91, P < 0.0001). Furthermore, there was excellent correlation between the measured and estimated LV dp/dt(max) after changes in contractility with dobutamine in 10 randomly selected patients (y = 0.86 × x + 34.2, r = 0.77, P = 0.01). It is possible to estimate LV dp/dt(max) noninvasively in children using tonometry. This procedure can be useful for bedside assessment of LV contractility and the clinical management of patients with cardiovascular disease.     

Performance of the failing and nonfailing right ventricle of patients with pulmonary hypertension.

Hemodynamic performance of the right ventricle was measured in 34 patients: 17 with pulmonary hypertension, 9 with pulmonary hypertension and right ventricular failure and 8 control subjects. Among the patients with pulmonary hypertension who did not have right ventricular failure, right ventricular maximal isovolumic rate of development of ventricular pressure (dP/dt) was significantly elevated (P less than 0.001), whereas maximal 1/P dP/dt and maximal velocity of contractile element shortening (Vmax) were comparable with values observed in control subjects. The patients with pulmonary hypertension who had right ventricular failure also showed an augmented right ventricular maximal dP/dt (P less than 0.001) and normal 1/P dP/dt and Vmax. These observations indicate that in pulmonary hypertensive heart disease, even when the right ventricle failed in a clinical sense, the contractile effort was normal. Consequently, right ventricular failure may develop in patients with pulmonary hypertensive heart disease even though the cardiac muscle performs normally as a contractile tissue.     

Determinants of the relation between systolic pressure and duration of isovolumic relaxation in the right ventricle

Previous studies have suggested that right ventricular systolic pressure can be predicted from noninvasive estimates of the interval between pulmonary valve closure and tricuspid valve opening. To determine the basis for this relation, phonocardiograms and high fidelity right atrial and ventricular pressures were recorded in 29 patients with a right ventricular systolic pressure ranging from 20 to 149 mm Hg. In 22 patients with normal right atrial pressure (⩽ 8 mm Hg), both the time interval and the magnitude of pressure decrease from pulmonary valve closure to tricuspid valve opening were linearly related to systolic pressure (r = 0.89 and 0.96, respectively). Early pulmonary valve closure (decreased “hang-out” time) contributed to the greater magnitude of isovolumic pressure decrease at high systolic pressures, but correction for hang-out time did not eliminate the relation between systolic pressure and the pulmonary valve closure-tricuspid valve opening interval (n = 10).When patients with documented right coronary artery disease were excluded, the time constant for isovolumic pressure decrease also increased as a function of systolic pressure (r = 0.67, p < 0.01, n = 24), suggesting impaired relaxation at high systolic pressures. However, the mean rate of pressure decrease (mean negative dP/dt) still was greater in patients with a high pressure because of the exponential nature of the isovolumic pressure-time relation. The pulmonary valve closure-tricuspid valve opening interval accurately predicted normal systolic pressure in patients with right coronary artery disease despite markedly prolonged time constants, but was inappropriately short for the level of systolic pressure in patients with an elevated mean right atrial pressure because early opening of the tricuspid valve decreased the magnitude of isovolumic pressure fall.These findings indicate that 1) the magnitude of isovolumic pressure fall is the major determinant of the pulmonary valve closure-tricuspid valve opening interval, 2) pulmonary hypertension prolongs the interval by increasing both the magnitude and the time constant for pressure fall, and 3) the determinants of this interval can be altered by factors other than systolic pressure.     

Non-invasive radial pulse wave assessment for the evaluation of left ventricular systolic performance in heart failure

INTRODUCTION: Left ventricular (LV) developed pressure (dP/dt) is a classical index of myocardial contractility related to prognosis during heart failure. We sought to assess the reproducibility and feasibility of use of the maximal first derivative of the radial pulse, Rad dP/dt, as a peripheral criterion of ventricular contractility in patients with heart failure. METHODS: We assessed 50 consecutive, patients with heart failure using aplanation tonometry to record the radial pulse wave and calculate Rad dP/dt. Echocardiography, Doppler flow and tissue Doppler imaging were used to record classical parameters of LV function: LV ejection fraction (LVEF), Tei index, dP/dt on mitral regurgitation (MR dP/dt) and peak systolic velocity (S'). Total systemic vascular resistance (TSVR) was calculated by use of the Doppler calculated cardiac output. Preload was assessed by the E/Ea ratio. Feasibility was tested in an ongoing prospective mortality study (n=310). RESULTS: The Bland and Altman representation of repeated measurements of the Rad dP/dt showed good agreement. Feasibility was greater than 99% for a successful assessment on the right arm during the first attempt. The Rad dP/dt correlated with the LVEF, S' or Tei index as usual parameters of impaired contractility but not preload (E/Ea) or afterload (TSVR) parameters. MR dP/dt and Rad dP/dt were closely related (r=0.75, p<0.001). The ability of the arterial dP/dt to characterize LVEF was not modified by adjustment for arterial viscoelastic properties. CONCLUSION: The maximal dP/dt of the radial pulse appears to be a valuable and reproducible peripheral criterion of LV systolic performance.     

Can echocardiographic evaluation of cardiopulmonary hemodynamics decrease right heart catheterizations in end-stage heart failure patients awaiting transplantation?

Candidacy for heart transplantation is influenced by the severity of pulmonary hypertension. In this study, invasive hemodynamics from right-sided cardiac catheterization were compared with values obtained by validated equations from Doppler 2-dimensional transthoracic echocardiography. This prospective study was conducted in 40 patients with end-stage heart failure evaluated for heart transplantation or ventricular assist device implantation. Transthoracic echocardiography and right-sided cardiac catheterization were performed within 4 hours. From continuous-wave Doppler of the tricuspid regurgitation jet, pulmonary artery systolic pressure was calculated as the peak gradient across the tricuspid valve plus right atrial pressure estimated from inferior vena cava filling. Mean pulmonary artery pressure was calculated as (0.61 × pulmonary artery systolic pressure) + 2. Pulmonary vascular resistance (PVR) was calculated as (tricuspid regurgitation velocity/right ventricular outflow tract time-velocity integral × 10) + 0.16. Pulmonary capillary wedge pressure was calculated as 1.91 + (1.24 × E/E'). Pearson's correlation and Bland-Altman analysis of mean differences between echocardiographic and right-sided cardiac catheterization measurements were statistically significant for all hemodynamic parameters (pulmonary artery systolic pressure: r = 0.82, p < 0.05, mean difference 3.1 mm Hg, 95% confidence interval [CI] -0.2 to 6.3; mean pulmonary artery pressure: r = 0.80, p < 0.05, mean difference 2.5 mm Hg, 95% CI 0.3 to 4.6; PVR: r = 0.52, p < 0.05, mean difference 0.8 Wood units, 95% CI 0.3 to 1.4; pulmonary capillary wedge pressure: r = 0.65, p < 0.05, mean difference 2.2 mm Hg, 95% CI 0.1 to 4.3). Compared with right-sided cardiac catheterization, PVR by Doppler echocardiography identified all patients with PVR > 4 Wood units (n = 4), 73% of patients with PVR <2 Wood units (n = 8), and 52% of patients with PVR from 2 to 4 Wood units (n = 10). In conclusion, echocardiographic estimation of cardiopulmonary hemodynamics is reliable in patients with end-stage cardiomyopathy. The noninvasive assessment of hemodynamics by echocardiography may be able to decrease the number of serial right-sided cardiac catheterizations in selected patients awaiting heart transplantation. However, in patients with borderline PVR, right-sided cardiac catheterization is indicated to assess eligibility for transplantation.     

A new method for estimating left ventricular dP/dt by continuous wave Doppler-echocardiography. Validation studies at cardiac catheterization

In this study, we explored the use of continuous wave Doppler-echocardiography guided by color Doppler flow-mapping as a method for noninvasively calculating the rate of pressure rise (RPR) in the left ventricle. Continuous wave Doppler determination of the velocities in mitral regurgitant jets allows calculation of instantaneous pressure gradients between the left ventricle and the left atrium. Left atrial pressure variations in early systole can be considered negligible; therefore, the rising segment of the mitral regurgitation velocity curve should reflect left ventricular pressure increase. We studied 50 patients (mean age, 51 years; range, 25-66 years) in normal sinus rhythm with color Doppler-proven mitral regurgitation and compared the Doppler-derived left ventricular RPR with peak dP/dt obtained at cardiac catheterization. Doppler studies were performed simultaneously with cardiac catheterization in 11 patients and immediately before in the remaining cases. Two points were arbitrarily selected on the steepest rising segment of the continuous wave mitral regurgitation velocity curve (point A, 1 m/sec, point B, 3 m/sec), and the time interval (t) between them was measured. Following the Bernoulli relation, the pressure rise between points A and B is 32 mm Hg (4vB2-4vA2) and the RPR is 32 mm Hg/t. Results showed a linear correlation between the Doppler RPR and peak dP/dt (r = 0.87, SEE = 316 mm Hg/sec). The RPR in the left ventricle can be derived from the continuous wave Doppler mitral regurgitation velocity curve.